In data centers and other industrial environments, a power source is typically provided to information technology (“IT”) equipment with a three-phase busway that carries current. Each phase can be provided separately to different types of IT equipment. In some instances, the three-phase busway provides power to a rack that holds electrical equipment such as servers. The IT equipment located in the rack receives power from the busway via a PDU mounted to the rack frame. The PDU includes a connection to the three-phase busway, and a plurality of components to provide, regulate, and monitor the current being distributed to the IT equipment in the rack. Some examples of the components used in such a PDU include outlet modules, communications modules, circuit breakers, and sensors.
Some PDUs include three circuit breakers, one for each phase of the busway. The current from each busway passes through a circuit breaker before being distributed to an outlet, and then to the downstream equipment. Because the PDUs are mounted vertically in a rack frame, the outlets receiving current from a particular phase are typically clustered together in sections being approximately 16 inches long.
Phase balancing may be performed to improve the reliability of upstream electrical equipment, such as generators, switchgear, and 3-phase UPSs. Electrical utilities may also penalize customers if their loads are grossly unbalanced. However, in order for a user to balance the load on each phase of the PDU, the user must use varying lengths of cable to distribute the equipment connections evenly between the outlets of the three-phases. This process is cumbersome and inefficient for the user.
The circuit breaker connections to each outlet may be alternated. For example, the first outlet of every three outlets would be connected to the first circuit breaker, the second to the second circuit breaker, and the third to the third circuit breaker. Such a solution requires significant wiring, which increases the risk of connection errors at the manufacturing level and increases costs for labor and parts. The present disclosure provides an alternate method for providing the benefit of alternating the circuit breaker connections to alternating outlets, while eliminating the drawbacks of separately wiring each outlet to a circuit breaker.